41. Paleontologists have identified dozens of mass extinctions , of which five stand out as especially severe. 42. Buried rocks record many prehistoric mass extinctions , when much earthly life disappeared, as if overnight. 43. I think fast climate change in any direction is one cause for mass extinction events. 44. Another mass extinction ended the reign of the dinosaurs. 45. Giant dinosaurs developed after this period and were killed off in a different mass extinction . 46. Various causes have been suggested for the mass extinction , from climate change to asteroid impacts. 47. Ward said he was drawn to the topic because of his studies of mass extinctions . 48. They note the lack of correlations in the fossil record between flips and mass extinctions . 49. Pages on extinction and the sixth mass extinction specifically. 50. "For them, the mass extinction of dinosaurs just meant a menu change, " said Ribeiro.
